High efficiency power supplies are desirable for battery-operated systems, including mobile phones, tablets, laptops and other user devices. Increased power density, reduced circuit size, and lowered costs are desired properties of switching converters for many such applications. Many DC to DC converter topologies, such as buck, boost, buck-boost, cuk and other configurations, use high and low side transistor switches or drivers to alternately connect a switching node to the input voltage or ground. Switching converter efficiency is largely influenced by switching losses and conduction losses. Laterally diffused MOS (LDMOS) transistors are a type of extended drain transistor (e.g., DEMOS) sometimes used in power switching circuits and other applications in which high voltage transistors are integrated with logic and other low voltage transistors on a single integrated circuit (IC). DEMOS transistors are also available as standalone transistor products for use in constructing switching power supplies. LDMOS improvements are desired to further improve efficiency, increase switching frequency, and to reduce size and system cost.